Dr. Julie Palais (l.) and Anais Orsi examine ice inside a backlit snow pit at the WAIS Divide. The horizontal lines represent annual layers of snowfall. The two to three feet of snow that falls each year compacts over time into a narrow band of ice. See more pictures from the WAIS Divide Ice Core project here: http://bit.ly/13DseAk

"We're trying to home in on how our climate changes, on the scale of years and decades rather than on the scale of thousands of years, which we've never been able to do in Antarctica before," says T.J. Fudge, the lead author on the paper. "I think that's going to tell us so much about how our climate system works, at the short time scales that are relevant to modern climate change."

Most of Antarctica's oldest ice is up in the eastern mountains, where cold air and steep terrain insulate the ice fields from the surrounding ocean and atmosphere. Climate researchers have focused on the 800,000-year climate record preserved there, discounting two previous ice cores taken in the west. One of the western cores was taken on a glacier, so its ice had moved away from the spot that the snow first fell; the other was taken at the edge of the Ross Ice Sheet, so its ice layers are vulnerable to ocean changes that can mask climate changes.

"So many good records came out of East Antarctica [that] the West Antarctic records have been forgotten a little bit," says Mr. Fudge, who is a graduate student in glaciology at the University of Washington.

But because West Antarctica is more influenced by storms and changes in sea ice, it's also much more sensitive to atmospheric changes – the very changes that make for a detailed and useful climate record.